Itinerant electron metamagnetism at finite temperature

An itinerant electron metamagnetism at finite temperature is discussed by taking into account the effect of spin fluctuations. The metamagnetic transition from the paramagnetic to ferromagnetic state is qualitatively shown to occur only below a critical temperature, which is lower than that at which the paramagnetic susceptibility shows a maximum in its temperature dependence. Moreover, a condition for the first-order transition, induced by the spin fluctuations, in the temperature dependence of the spontaneous magnetization is found, connecting with the Landau-Belov expansion coefficients.